As a bystander, I definitely agree that Retell's demo wins on latency — it felt pretty close to human. The voice also sounds more natural to my ears (not sure why, since Nero is apparently using Eleven Labs for voices, and Eleven's voices usually sound pretty good to me).

Playing around with the Nero demo, it also feels pretty... broken? I never actually managed to make a booking with Nero; it seemed to often not be able to tell I was done speaking, and would just hang after a couple back-and-forths. Still impressive for a one-man demo built quickly, but they don't feel in the same league.

I do wish Retell's pricing was cheaper, though; $6/hr is pretty much the cost of a call center employee in India, and LLMs still perform below the average human on most things. That being said, I imagine the cost of Retell will come down as the tech advances, and LLMs will also improve over time.